Sufficient conditions of the various stabilities of the linear time-varying delayed differential equations

Due to the appearance and the study of the ornithopter and flexible-wing micro air vehicles, etc., the time-varying systems become more and more important and ubiquitous in the study of the mechanics. In this letter, the sufficient conditions of the uniform asymptotic stability are first presented for the delayed time-varying linear differential equations with any time delay by employing the Dini derivative, Lozinskii measure and the generalized scalar Halanay delayed differential inequality. They are especially based on the estimation of the arbitrary solutions but not the fundamental solution matrix since their solutions＇ space is infinite-dimensional. Then some sufficient conditions of the stability, asymptotic stability and uniform asymptotic stability of the delayed time-varying linear system with a sufficiently small time delay are reported by employing Taylor expansion and Dini derivative. It implies that these stabilities can be guaranteed by the Lozinskii measure of the matrix composing of the time delay and the coefficient matrices of the system.

H_-/H_∞ fault detection filter design for interval time-varying delays switched systems

The problem of the robust fault detection filter design for time-varying delays switched systems is considered in the framework of mixed H-/H∞. Firstly, the weighted H∞ performance index is utilized as the robustness performance, and the H- index is used as the sensitivity performance for obtaining the robust fault detection filter. Then a novel multiple Lyapunov-Krasovskii function is proposed for deriving sufficient existence conditions of the robust fault detection filter based on the average dwell time technique. By introducing slack matrix variable, the coupling between the Lyapunov matrix and system matrix is removed, and the conservatism of results is reduced. Based on the robust fault detection filter, residual is generated and evaluated for detecting faults. In addition, the results of this paper are dependent on time delays,and represented in the form of linear matrix inequalities. Finally,the simulation example verifies the effectiveness of the proposed method.

时滞半Markov切换随机系统输入–状态稳定性分析的时变驻留时间条件方法

本文针对时滞半Markov切换随机系统,建立了一种基于时变驻留时间条件的不定多重Lyapunov-Razumikhin函数方法,给出了系统输入–状态稳定性和积分输入–状态稳定性判别条件.一方面,构造了一种不定多重Lyapunov函数,不要求每个子系统对应的Lyapunov-Razumikhin函数导数总是保持负定,从而放宽了对于子系统稳定性要求,甚至允许了不稳定子系统的存在;另一方面,提出了一种时变驻留时间条件来表示半Markov切换信号的切换次数与子系统驻留时间之间的关系,利用时变函数对切换次数进行估计,间接放松了不定多重Lyapunov-Razumikhin函数选取的限制.最后,数值算例验证了所提方法的有效性.

Robust stability analysis of switched uncertain systems with multiple time-varying delays and actuator failures

In this paper,the robust stability issue of switched uncertain multidelay systems resulting from actuator failures is considered.Based on the average dwell time approach,a set of suitable switching signals is designed by using the total activation time ratio between the stable subsystem and the unstable one.It is first proven that the resulting closed-loop system is robustly exponentially stable for some allowable upper bound of delays if the nominal system with zero delay is exponentially stable under these switching laws.Particularly,the maximal upper bound of delays can be obtained from the linear matrix inequalities.At last,the effectiveness of the proposed method is demonstrated by a simulation example.

地铁折返站折返能力计算及其参考图研究

列车折返能力不仅是确定城市轨道交通全线列车运输能力的基础,也是整个城市轨道交通系统运营组织的关键。一般情况下,车站折返能力大小决定了线路的最大通过能力,因此为保证整个地铁的最大通过能力、节约设备费用、降低运营成本,必须要合理有效的设计折返站车站型式。本文调研了国内外部分城市起终点站采用的折返方案现状,对典型站前站后折返车站进行分析,立足于对主要折返流程进行的细化模拟计算,总结出影响折返能力的诸多因素:如系统能力、线路条件、道岔型号、车辆参数、停车时间等,并进行详细分析,从而提出折返站应优先推荐采用站后折返型式、分期建设线路采用站前折返时宜尽快延伸、站前折返可通过增加停车线来改进折返流程、提高道岔型号以提高折返速度和减少线间距缩短道岔区占用时间以提高系统能力等方案。